Build action failing (bad public key?)

[angrave]

Describe the bug
The Deploy github action is failing -

https://github.com/illinois-cs241/coursebook/actions
https://github.com/illinois-cs241/coursebook/actions/runs/7253956531/workflow

To Reproduce
Accept a PR to the default branch

Expected behavior
New coursebook (epub+pdf etc) should be built and deployed.

gpg: directory '/home/runner/.gnupg' created
gpg: keybox '/home/runner/.gnupg/pubring.kbx' created
gpg: AES256.CFB encrypted data
gpg: encrypted with 1 passphrase
gpg: AES256.CFB encrypted data
gpg: encrypted with 1 passphrase
Agent pid 1977
Switched to a new branch 'epub_deploy'
[epub_deploy (root-commit) b634fe5] Adding build on Mon Dec 18 21:21:51 UTC 2023
Author: github-actions@github.com
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 main.epub
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.